/**
 * Copyright (C) 2021 - 2031 O-Cubes Co., Ltd.
 */

/****************************************************************
 *  @file    aes.h
 *  @brief   AES algorithms header file
 *  @version v1.0
 *  @date    03. Apr. 2023
 ****************************************************************/

#ifndef __AES_H__
#define __AES_H__

#include "common.h"

#ifdef __cplusplus
extern "C" {
#endif

#define AES_MIN_KEY_SIZE         16
#define AES_MAX_KEY_SIZE         32
#define AES_KEYSIZE_128          16
#define AES_KEYSIZE_192          24
#define AES_KEYSIZE_256          32
#define AES_BLOCK_SIZE           16
#define AES_MAX_KEYLENGTH        (15 * 16)
#define AES_MAX_KEYLENGTH_U32    (AES_MAX_KEYLENGTH / sizeof(u32))

/*
 * Please ensure that the first two fields are 16-byte aligned
 * relative to the start of the structure, i.e., don't move them!
 */
struct crypto_aes_ctx {
	u32 key_enc[AES_MAX_KEYLENGTH_U32];
	u32 key_dec[AES_MAX_KEYLENGTH_U32];
	u32 key_length;
};

/*
 * validate key length for AES algorithms
 */
static inline int aes_check_keylen(unsigned int keylen)
{
	switch (keylen) {
	case AES_KEYSIZE_128:
	case AES_KEYSIZE_192:
	case AES_KEYSIZE_256:
		break;
	default:
		return -1;
	}

	return 0;
}

/**
 * ECB(Electronic Codebook Book) mode
 */

/**
 * aes_expandkey - Expands the AES key as described in FIPS-197
 * @ctx:	The location where the computed key will be stored.
 * @in_key: The supplied key.
 * @key_len:	The length of the supplied key.
 *
 * Returns 0 on success. The function fails only if an invalid key size (or
 * pointer) is supplied.
 * The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
 * key schedule plus a 16 bytes key which is used before the first round).
 * The decryption key is prepared for the "Equivalent Inverse Cipher" as
 * described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
 * for the initial combination, the second slot for the first round and so on.
 */
int aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
		  unsigned int key_len);

/**
 * aes_encrypt - Encrypt a single AES block
 * @ctx:	Context struct containing the key schedule
 * @out:	Buffer to store the ciphertext
 * @in: 	Buffer containing the plaintext
 */
void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);

/**
 * aes_decrypt - Decrypt a single AES block
 * @ctx:	Context struct containing the key schedule
 * @out:	Buffer to store the plaintext
 * @in: 	Buffer containing the ciphertext
 */
void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);

#ifdef __cplusplus
}
#endif

#endif /* __AES_H__ */

